Kino is a young pearl diver living in La Paz, Mexico in the 1930s with his wife Juana and baby son Coyotito. Their tranquil life is disrupted when Coyotito is stung by a scorpion and poisoned. Unable to pay the doctor's high fees, Kino and Juana set out to find help, unwittingly beginning a chain of events that endangers their lives and family when Kino discovers a giant pearl.